/// <summary>
        /// Opens the symbol list editor.
        /// </summary>
        /// <param name="sender">
        /// A <see cref="System.Object"/>
        /// </param>
        /// <param name="arg">
        /// A <see cref="EventArgs"/>
        /// </param>
        private void OnSymbolListEditorItem(object sender, EventArgs arg)
        {
            SymbolLabelDialog dialog =
                new SymbolLabelDialog(mainWindow);

            dialog.Show();
            dialog.Destroy();
        }
        /// <summary>
        /// Handles the activation of the edit symbols menu item.
        /// </summary>
        /// <param name="sender">
        /// A <see cref="System.Object"/>
        /// </param>
        /// <param name="args">
        /// A <see cref="EventArgas"/>
        /// </param>
        private void OnSymbolsEditItemActivate(object sender, EventArgs args)
        {
            SymbolLabelDialog dialog =
                new SymbolLabelDialog(mainWindow);

            dialog.Show();
            dialog.Destroy();

            symbolLabelEditor.LoadSymbols();
        }